Jacob d



(No Model.) 2 Sheets-Sheet 1.

J. D. 00X, Jr. MECHANISM FOR BACK CLEARING TWIST DRILLS.

Patented July 23, 1889.

N. PETERS, Filulml-ilhoglapher. Washington. D C.

(No Model.) 2 Sheets-Sheet 2.

J.D.G0X,Jr. MEUHANIS-M FOR BACK CLEARING TWIST DRILLS.

No. 407,721. Patented July 23,-1889..

Witnesses N. PETERS. PholQLilhOmphnt. Washington. D C- UNITED STATES PATENT OFFICE.

JACOB D. COX, JR, OF CLEVELAND, OHIO, ASSIGNOR TO COX 8: PRENTISS, OF SAME PLACE.

MECHANISM FOR BACK-CLEARING TWIST-DRILLS.

SPECIFICATION forming part of Letters Patent N0. 407,721, dated July 23, 1889.

Application filed January 24, 1887. Serial No. 225,255. (No model.)

To all whont it ntay concern:

Be itknown that I, JACOB D. COX, J r., a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Mechanism for Back-Clearing Twist-Drills; and I do hereby declare that the followingis a full, clear, and exact description of the invention, whichwill enable others skilled in the art to which it appertains to make and use the same.

This invention relates to an. improved mechanism for the process known as back-clearin g twist-drills or twist-reamers, by means of which I impart to the revolving metal-removing wheels or cutters a reciprocating motion.

Referring to the drawings, Figure 1 is a side elevation of a machine constructed so as to embody my invention. Fig. 2 is an end view looking toward the right hand of Fig. 1. Fig. 3 is a plan of said machine. Fig. 4c is an end View looking toward the left-hand end of Fig. 1. Fig. 5 is a longitudinal section through the center of Fig. 4. Fig. 6 is a cross section or line of Fig. 1 on the line of the two adj usting-screws N N.

In the drawings, A is a former with a spiral groove a cut on it uniform with the spiral groove in the drill to be operated upon. The former is supported in a suitable bearing l3 and adjustable on spindle C and rotated by means of the worm-gear F, which is driven by the worm G and pulley X, both on the shaft G. In the bearing or frame B is contained a suit. bly-shaped pin D, which at its lower end enters the groove in the former A. This pin is held in place by means of the yoke E and set-screw E, which bears upon the pin. By rotating the pulley X this train of mechanism is set in motion, and the former A is not only revolved, but is carried forward, thus imparting to the drill to be operated upon,

which is held in the spindle C by a suitable chuck or socket, a corresponding spiral motion.

J J are emery-wheels suitably mounted on spindles or shafts L L, which are carried in the frames K K and driven by the pulleys S S and suitably-arranged belts. The frames K K have a sliding movement or adjustment toward or from the spindle C by means of the screws N N and the planed surfaces on the pieces K K to adapt the machine to drills of various diameters. The pieces K K have a movement at right angles to that of the frames K K by means of properly-planed surfaces 011 the pieces K K The pieces K K are bolted down onto the frame or bed of the machine in such manner that they can be swung round through part of a circle of which the bolts U U are the center.

R is a guide or bushing holder carrying an adjustable guide or bushing P.

Z Z are circular or other suitably-shaped pieces mounted on the ends of the shaft G, having properly-shaped grooves cut across their faces to hold the adjustable pins H H. The piece Z in this instancethat is, on the left of the drawingsis combined with and forms a part of the pulley X to reduce the number of pieces. The pins H H are connected with the pins H H in the pieces K K by means of the connecting-rods H H, and as the pieces Z Z revolve with the shaft G the circular motion 'of the pins H H is converted into a reciprocating motion, which is communicated to the pieces K K. The pins H H might be firmly and immovably fixed in the crank-plates Z Z; but I prefer to have them movable, so as to adjust the length of the stroke of the pieces K K, and through them the emery-wheels J J or the metal-removing devices used, io suit the different sizes of drills to be operated upon.

The operation of my invention is as follows: The drill I to be, operated upon is placed in the socket or chuck on the end of the spindle C. By means of the crank-handle 1 the former A is rotated and advanced until the point of the drillis entered in the jaws of the supporter or guide P. By loosening the drill in the chuck or the spindle in the former A the drill can be rotated until what is to be the cutting-edge is brought to the proper 95" place to just escape the action of the wheels J. J. The screws U U and U U may now be loosened and the right-hand ends of the pieces K K moved slightly toward each other, where they are secured tightly in place, thus causing the sliding pieces K K, if moved at all, to gradually approach or recede from each other. The wheels J J are now advanced toward each other, by means of the screws N N and hand-levers or cranlchandles 2 2, until they remove the desired quantity of metal from the drill to be operated upon, and then set in motion by a suitably arranged countershaft and belts on pulleys S and run continuously, while an indefinite number of drills of the same size are operated upon. The former A must now be tightened on the spindle O, the worm G placed in mesh with the worm- 7 wheel F and started in motion by suitablyvolving at the proper speed. The disk-cranks Z Z are also set revolving by the same belt that drives the worm G. Consequently the sliding pieces K K are caused to move forward and backward by means of the crankpins H H, the connecting-rods H H, and the connecting-pins H H The pieces K K, by the adjustment-- of the plates K K move in lines at a slight angle with the axis of the drill I. Consequently the wheels J J will remove more metal from the right-hand edge of the land in the drill than from the left hand or cutting edge, thus producing the desired backclearance. In practice it is found desirable to so adjust the movable crank-pins H H that the stroke or travel of the slides K K will be greater than the distance in a straight line parallel with the axis of the drill from one edge of the land to the other at its widest part, which will be near the shank end, and to so set the pieces K K that the wheels will cut sufficient metal off from the back edges of the drill and entirely leave the drill just before reaching the cutting-edge and the end of the stroke.

It is possible and practical to so construct the machine that the slides mounted on the pieces K K? may be mounted on the bed or frame of the machine, and they may be either at a slight angle to the axial line of the drill or parallel thereto. In the latter event the stroke of the slides K K must be so adjusted by means of the movable crank-pins H H as to cause the wheels J J to approach close to but not pass over the cutting-edge of the drill. This arrangement would leave the cleared portion of the drill in the form of a cylinder, and the cutting-edges would be raised up in ridge-like prominences throughout their entire length.

In the drawings the traveling motion of the wheels J J is imparted thereto by connection with the crank-pins H H, through the connecting-rods H H, the pins I-l H and the slides K K. It is also obvious that any metal-removing devicessuch as milling-cutters of rotary filescould be substituted for the emery-wheels J J. In practice I prefer emery-wheels of a relatively-narrow face, as the shape or amount of clearance does not depend at all upon the width of face of said wheels.

In my improved machine the wheels, by reason of their reciprocating movement over the land to be out, while at the same time they are revolving at a high rate of speed, bring all their working-surface equally into service, and can be run without any dressing whatever until entirely worn out.

I am aware that twist-drills have been backcleared on both sides at once, but never in the manner above described. It is also obvious that the means herein described for establishin g a reciprocating motion between the metalremoving devices and the drill may be so far modified as to merely reverse the order of their operation and make the removing devices the fixed members of the machine while the drill is reciprocated instead. In that case the metal-removing devices would revolve, but be otherwise stationary in action, and a back-and-forth movement would be given to the drill-shaft and. the mechanism and support with which it is immediately connected but the construction shown is considered preferable and gives entire satisfaction.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a machine for back-clearing twistdrills,a supporting-bed,apair of frames, each carrying a metal-removing device, and converging guides between the bed and frames, in which the frames are adapted to reciprocate, in combination with the driving-shaft and connections with the pair of frames to reciprocate the said frames, substantially as set forth.

2. In a machine for back-clearing twistdrills, a pair of frames provided with metalremoving devices and supported on the bed in converging guides, with a spindle which carries the drill, said spindle located on the bed with the line of its axis extending between the metal-removing devices, in combination with the driving-sh aft, and connections between said shaft and the frames aforesaid to reciprocally operate said frames, substantially as set forth.

IIO

3. In a machine for back-clearing twistparts connecting" the shaft and the frames to reciprocate the frames and the metal-removing devices, substantially as set forth.

. 5. In a machine for back-clearing twistdrills, a supporting-bed, a pair of revolving metal-removing devices, and a spindle for holding the drill set with the line of its axis projecting between said metal-removing devices, in combination with separate frames which carry the metal-removing devices, and guides on the supporting-bed in which said frames are adapted to be reciprocated, substantially as set forth.

6. In a twist-drill-clearing' machine, a supporting-bed, a pair of metal-removing devices supported upon separate sliding pieces adapt.

ed to be reciprocated, in combination with a drill-advancing shaft provided with a gearwheel, a shaft having a Worm meshing with said gear-wheel, and rods connecting the said sliding pieces with the ends of the wormshaft, substantially as set forth.

JACOB D. COX, JR. WVitnesses:

H. T. FISHER, WM. M. MONROE. 

